There are known in the art numerous fertilizing formulations based on humates and/or humic extracts obtained from fossil sources. However, said formulations have problems both from a qualitative and a quantitative point of view, in that they lead to unsatisfactory agronomic results.
Humic acids have important functions in both soil and plants. In soil they bind to macro and micro elements, in particular to phosphorus and iron, enhancing their bioavailability to plants and at the same time avoiding insolubilization caused by high pH and high percentages of active limestone. In addition, they enhance biodegradation of toxins produced by plants, of active compounds and of many pollutants of organic origin.
They also improve the chemical, physical and biological properties of the soil, increasing the carbon of biological origin, which acts as an important catalyst in the process of assimilation of nutrients to crops.
More generally, humic acids are known to promote seed germination, development and fortification of the root system, as well as improving the overall biochemical activities of the plant and soil. U.S. Pat. No. 4,698,090 describes a process for the preparation of a liquid composition used to improve the growth of plants, in which a leonardite based mineral is reacted with an organic chelating agent in aqueous medium at a temperature between 77-107° C. Among the chelating agents used are, for example, gluconic acid, glucaric acid, glutaric and glutamic acid or glutamine and synthetic chelating agents such as EDTA.
U.S. Pat. No. 4,786,307 describes a process for the preparation of liquid fertilizers, in which the product obtained after the extraction of the leonardite base material in water with a chelating agent consisting of a salt of a hydroxy acid at a pH>2.5 is combined with a metal salt of a micro-nutrient metal in the presence of a hydroxy acid with the subsequent addition of anhydrous ammonia in the reaction mixture in order to bring the pH to value between 7.5 and 9. The synthetic chelating agents include: ethylenediamine acid-N-bis(2-hydroxyphenylacetic) (EDDHA), ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaacetic acid (DTPA) and are characterized by a very high environmental impact. In fact, they are quickly leached away into the ground water and thus could pollute the waters and the soil.
PCT International Application WO 2004/110962 describes a process for the preparation of fertilizers in solid and liquid form based on fossil materials, having a high content of humic acids, in particular leonardite, characterized by the use of water and gluconic acid and the subsequent extraction of the humic acids in the presence of an alkaline agent such as potassium hydroxide or ammonium until obtaining a pH>9.
PCT International Application WO 2010/013275 describes a process for the formulation of compositions of natural fertilizers and surfactants for washing, reclamation and cultivation of contaminated soils and compositions in liquid and solid form comprising the use of alginic acid and, as a means of extracting potassium hydroxide or ammonium hydrate or their association, to obtain a product with an extremely high pH.
In light of the above, environmentally friendly technological formulations, such as fertilizers and resistance inducers, which overcome the many disadvantages of the formulations known in the art are needed.